import XCTest class SomeTests: XCTestCase { override class func setUp() { super.setUp() UserDefaults.standard.set("en_US", forKey: "AppleLocale") UserDefaults.standard.set(["en_US"], forKey: "AppleLanguages") UserDefaults.standard.synchronize() } override class func tearDown() { super.tearDown() UserDefaults.standard.removeObject(forKey: "AppleLocale") UserDefaults.standard.removeObject(forKey: "AppleLanguages") UserDefaults.standard.synchronize() } }